I too had the barrel screw come loose on my new Ruger SR22. In fact, I fired at least 200 rounds through mine WITHOUT the barrel screw; with the barrel just sitting there. I was experiencing frequent jams, and the gun just felt sloppy, and hard to aim; duh! I did not realize the barrel was lose until taking it apart for cleaning. Ruger is sending me a new barrel screw and lock washer via priority mail--at no charge of course.